When data in a disk drive are being processed, disk access is less efficient than memory access due to the influences of the of disk access counts and the seek time. Therefore, to optimize the disk access of stored data in a storage apparatus, it is desired that a set of data which are to be accessed concurrently be stored as much as possible in the same segment of the disk.
References may be made to Japanese Laid-open Patent Publication No. 07-319902 and International Publication Pamphlet No. WO 2013/114538.